Reinforced grid resistance.



H. J. WIBGAND.

REINPORGED GRID RESSTANGE.

APPLICATION 'FILED MAY 4,1908.

Patented Sept. 10,1912.

UNrrED sTArEs Parana oratori.

riff-- IIENRY J'. WIEGAND, 0F MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUT'LER- HAMMER MFG. CO., 0F MILWAUKEE, WISCONSIN, A ACORIORAIION OF WIS- CONSIN.

REINFORGE'D GRID RESISTANCE.

Specification of Letters Patent. Patented Sept. 10, 1912.

Application tiled. May 4, 1908. Serial No. 430,843.

the grid comprises a long refleXed bar it is more or less flimsy. To stiffen and strengthen the grid as a whole, reinforcing strips B are placed over the edges thereof, or, in other words, over the ends of the bars thereof.

The reinforcing members may assume any desired form, but in practice, are preferably formed of thin strips of metal so bent as to be U-shaped in cross-section. In practice, it is desirable to interpose a yielding packing between the reinforcing members and the grid, as resistances of this type arerather brittle and are easily damaged if held too rigidly by the reinforcing members.A Furthermore, it is necessary to insulate the 'reinforcing members from the grid.` I. therefore, interpose alayei.' of yielding and noncombustible insulating material@ between the grid and each of the reinforcing members. While any suitable material may be employed for this purpose, I prefer to use asbestos. To obviate lthe danger of shortoireuits through a reinforcing member, should the asbestos become. wet, I interpose a layer of waterproof insulating material D between the same. The waterproof material should be arranged to completely separate the reinforcing members from the asbestos, and thus render contact between the same impossible. lating material, such as mica or miconite, may be employed for this purpose, and if desired, the same may assume the form of a paint which may be applied to either the inside of the reinforcing members or the outside of the asbestos strips. The strips of asbestos and a waterproof material are first folded over the edges of the grid and then the reinforcing members clamped thereon in any desired manner. By making the outer bars a of the grid of the same length as the intermediate bars,the ends thereof will be gripped by the reinforcing strips and this gives additional strength and rigidity to the grid.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

To all whom t may concern:

Be it Ilmown that I, HENRY J. VIEGAND, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of IisConSin, have invented new and useful Improvements in Reinforced Grid Resistances, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specificatlon.

My invention relates to improvement in reinforced*l grid resistances and those of similar form.

My invention has .for its object to provide means for rendering short-circuits through the reinforcing members of the grid impossible under all conditions.

According to the preferred form of my invention I interpose two layers of insulating material between each of the reinforcing members and the grid, one layer comprising a yielding and non-combustible material, and the other comprising a waterproof material. I interpose waterproof material between the reinforcing member and the yielding insulating.material to maintain the same out of cont-act. It should be understood that any insulating materials having the properties mentioned may be em.- ployed.

In the accompanying drawing which illustrates the preferred embodiment of my inveution: Figure l is an elevation of a reinforced grid resistance embodying my invention, part of the reinforcing means being shown in section. Fig. Q is a sectional view taken on line Q2, Fig. 1, and Fig. is an enlarged det-ail view of a portion of Fig. 2.

My invention applies particularly Ito. resistances which comprise a refieXed bar or. strip having a series of convolutions,. such as a grid resistance A illustrated in the accompanying drawing. This type of resistance is used extensively in practice and is usually made of cast iron, but may be made of any suitable material and formed in any desired manner. The outer bars a" of the grid are provided with terminals a? by 1. The combination with a resistance elemeans of which the grid may be supported ment, of a reinforcing member embracing and electrically connected in circuit. The. portions thereof and means interposed beouter bars e. are preferably made of the l "meen said reinforcing member and said same length as the intermediate bars for the resistance element for providing resilient purpose hereinafter set forth. Inasmuch as and waterproof insulation between the same.

Any suitable waterproof insu- 2. The combina-fion with a grid feesb` ance, eff an elo'ngzl'ied Sheet mea strip famed. over the ends ef 'the eonveutons of said grid for reinforcing the Same. and menne um'posed between said strip and said. grid mf l fvdng a yielding and wnterpree-f in sului'ioe bemeen the same.

"11. The cembim'on with a grid resistance, yenfe'cne strips placed ove? the edges heeof., lnjvel Viedng nsuaing maiere and a layer 01:' Waffel/'proof insulating mney interposed between each of Said re iuf'ocing strips and said grid, the Wateyproef material being ne'posed beween 'he ,reju'`,u' :ing slips and the yielding ilsl'elag g umeral.

4. "She combination Wi'h a: grid resistance, of subemnialy Uehaped-renforeng .strips Eplaced over the edges thereof a. sie@ 0; i asbestos and. :L lag/e1' of watepoo metela uterpoeed between eachl of said, members and said grid, the waterproof matera being n'erpeeec between he reinfoeng strips; :md the eebes'es strips.

"In Witness Whereo' have hereunto sub- Serie-ed my name in' the presence of two W'- nessus'.

HENRY J. VVIEGANQ.

4Wnegsee M L. HOPKINS,

2eme-s of this patent may be obtained for ve cents eeen, by addfessng he Gommissoner of Fiatees,

Washington, D. C. 

